Jawabanmu

2014-05-05T11:27:45+07:00
W=f x s w=10 x 15 = 150 maaf kalau salah
2014-05-05T11:56:19+07:00
W = F x s
    = 10 x (20-5)
    = 10 x 15
    = 150 Joule <--

Semoga membantu :)